Circuit breaker



Oct. 11, 1938. JACKSON 2,132,628

CIRCUIT BREAKER Original Filed Aug. 15, 1935 INVENTOR J29]?? '62 Jae/52502 Patented Oct. 11, 1938 UNITED STATES CIRCUIT BREAKER John G. Jackson, De

Square D Compan tion of Michigan troit, Mich, assignor to Detroit, Mich., a corpora- Original application August 15, 1935, Serial No.

36,247. Divided and this application June 25,

' 1936, Serial No. 87,214

7 Claims.

This invention relates to devices for making and breaking electric circuits and more particularly to electric circuit breakers automatically operable in response to current overload.

The object of the present invention is the provision of an improved and simplified adjustable mounting means for a current responsive bimetallic strip in an automatic electric circuit breaker.

Other objects and features of the invention will be readily apparent to those skilled in the art from the following specification and appended drawing illustrating certain preferred embodiments of the invention in which:

Figure 1 is a vertical sectional view oi. the circuit breaker according to the present invention.

Figure 2 is a view on reduced scale of the mechanism shown in the lower part of Figure 1 20 in a different position.

Figure 3 is a detail bottom view of the bimetal mounting.

Figure 4 is a detail front view'of the bimetal mounting.

This application is a division of application, Serial No. 36,247, filed August 15, 1935, for Circuit breaker.

The circuit breaker illustrated in the drawing comprises an exterior enclosing box I having a 3 movable cover 2. Within the enclosure is mounted a scalable multi-circuit circuit breaker com-' prised of an insulating base 3 and metallic cover 4 sealably secured to the base by means of rivets 5. The cover 4 is provided with a plurality of openings through which extend the operating handles 6. The enclosure cover 2 is provided with a generally central opening receiving a raised portion of the cover 4 and exposing the operating handles 6 to the exterior of the enclosure. Within the circuit breaker is disposed a stationary contact plate 1 secured to the base by means of a stud 8. Cooperating with this contact plate are a plurality of floating contact bars 9 carrying contact surfaces I adjacent one end. The contact bars 9 are provided with notches II received within the upper ends of slots l2 within one of the legs of members I! which are guided by the base for rectilinear movement. Compression springs it bias the bars 9 for rotation about their pivotal engagement with the members I3. The operating handles 6 are generally L-shaped and have their interior legs provided with cam surfaces engaging the front of the members 19 to transmit 00 cation to be hereinafter described.

rotary movement of the handles into rectilinear At the opposite ends of the base, connectors ii are rigidly secured to the end flanges by spunover portions of metallic inserts I1 and the in-- terior ends of the connectors 18 have their central portions punched or pressed inwardly from the main portion of the connector as at 18. To this portion of each connector is rigidly welded or otherwise secured one end of a bimetallic strip l9. The side arms 2| formed at the end of the connectors are bent over as 211522 and within the spaces formed between the side arms 2|, the bent over portions 22 and the central portions 19 are disposed blocks 23 through which are threaded studs 24 hearing against the free ends of the central portions 19 and serving as adjusting and calibrating means for the bimetallic strips l9. Flexible leads 25 interconnect the free ends of the bimetallic strips l9 andintermediate points on the contact bars 9. The metallic inserts ll may be interiorly threaded for the reception of terminal studs 26. The ends of the circuit breaker may be sealed off by means of fibre sheets 21 secured between the engagement of the cover 4 with the top of base 3. v

The operation of the circuit breaker will now be described.

The mechanism shown at the bottom 01' Fig ure 1 is in the normal operating position with the movable contact I0 pressed against the contact plate I by the compression spring i4 and the contact bar 9 latchingly engaged at its opposite end by the bimetallic'strip 19. To move the parts to manual "off position the handle is rotated about its engagement with the metallic cover 4 into the position shown in reverse at the top of Figure 1, whereupon the cam surface formed by the interior leg of the handle moves the member I 3 toward the bottom of the base 3, thus forcing the contact carrying end of the bar 9 out of engagement with the plate I and interrupting the current through the mechanism affected. To again place the parts in closed circuit position the handle is rotated in the opposite direction.

When an overload occurs through any breaker mechanism while in the normal closed circuit position shown at the bottom of Figure 1, the bimetallic strip will flex or bend downwardly until it releases the contact bar 9 which will then rotate about its engagement with the member l3 under the bias of the compression spring I4, thus moving the parts into the position shown in Figure 2. As the spring is relatively weak compared with spring It, the release of the contact bar by the bimetallic strip results in the corresponding handle 6 being moved outwardly into its indicating position as shown in Figure 2. To reset the breaker mechanism after automatic trip, the handle is operated as a push button and upon pushing inwardlythe member I3 will be moved 2 arsaoas toward the bottom of the base whereupon the contact bar 9 will be rotated about its engagement with the member is until its latching end again moves in back of the latching end of the bimetallic strip. l9, whereupon if the bimetallic strip has in the meantime cooled sum ciently to resume its normal position, release'of the handle will permit the parts to assume the position shown at the bottom of Figure l.

The bimetal mounting herein disclosed constitutes a very simple and economical means for supporting and adjusting the circuit breaker. This mechanism involves a minimum of parts which can be readily assembled and it is seen that movement of the stud M will cause bending of the central pressed out portion 88 of the connector to move the free end of the bimetallic strip is so as to cause more or less overlapping of the contact bar 9 and hence to determine the value'of current which will cause the correspond ing breaker mechanism to operate .within a given length of time.

While the invention herein claimed has been disclosed in connection with the multi-clrcuit type of circuitbreaker claimed in the parent application, it is obvious that it is equally as Well adapted to single and multipole types of circuit breakers and to circuit breakers using distinctive mechanisms, and while certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto as many variations will be readily apparent to those skilled in the art and the invention is to be given its broadest possible interpretation within the terms of the following claims.

What is claimed is:

1. In an automatic electric circuit breaker, relatively movable contacts, means for automatically moving said contacts to separated position including a current responsive bimetallic strip, a scalable enclosure for said contacts and means, an electrical connector rigidly mounted at the exterior of said enclosure and forming a circuit terminal, said connector extending into said enclosure, one end of said bimetallic strip being rigidly secured to the connector adjacent to the interior end thereof, means electrically connecting the free end of the bimetallic strip to one of said relatively movable contacts, and means for controllably moving the interior end of said connector to provide adjusting means for the circuit breaker.

2. In an automatic electric circuit breaker having relatively movable contacts, manual means for effecting relative movement of said contacts to engaged and separated positions and automatic means for effecting relative movement of said contacts to separated position and including a current responsive bimetallic element, a scalable enclosure for said contacts, manual means and automatic means, a portion of said manual means extending through said enclosure to form an exterior operating handle, an electrical connector of generally L-shape, the base of the L being rigidly mounted at the exterior of the enclosure and forming a circuit terminal, the leg of the L being relatively free and extending into the interior of the enclosure, one end of the bimetallic element being rigidly secured adjacent tothe free end of said leg, means electrically connecting the free end of said element to one of said contacts, and means for controllably moving at least a portion of said leg to provide adjusting means for the breaker. i

3. In an automatic electric circuit breaker, relatively movable contacts, means for automatically moving said contacts to separated position including a current responsive bimetallic element, a connector rigidly supported at the exterior of the circuit breaker and having its interior end relatively free, a portion of said free end being movable relatively to the remaining portion of said free end, one end of said element being,

rigidly secured to said first portion, and means for controllably moving said first portion to adjust the circuit breaker.

s. In an automatic electric circuit breaker, relatively movable contacts, means for automatically moving said contacts to separated position includinga current responsive bimetallic strip, a connector leading to the exterior of the circuit breaker, the interior end of the connector having a center strip cut from the side portions and movablerelative thereto, one end of said bimetalhe strip being rigidly secured to said center strip,

means bridging said side portions, and a stud threaded in said bridging means and bearing against the center strip to provide adjusting means for the breaker.

5. In an automatic electric circuit breaker, relatively movable contacts biased to separated position, a current responsive bimetallic strip restraining such movement of said contacts, a rigid connector leading to the exterior of the circuit breaker, the interior end of said connector having a center strip bent from its normal plane, one end of said bimetallic strip being rigidly secured to the end of said center strip, means bridging the side pieces in the normal plane of the connector, and a stud threaded in said bridging means and bearing against said center strip to provide adjusting means for the breaker.

6. In an automatic electric circuit breaker, relatively movable contacts biased to separated position, a current responsive bimetallic strip re-' straining such movement of said contacts, a rigid connector leading to the exterior of the circuit breaker, the interior end of said connector having a center strip bent from its normal plane, one end of said bimetallic strip being rigidly se-' cured to the end of said center strip, a block having a tapped hole disposed between the main body of said connector and said center strip, a stud in said hole bearing against said center strip to provide adjusting means for the breaker, and means electrically connecting the free end of said bimetallic strip to one of said relatively movable contacts.

7. In an automatic electric circuit breaker, relatively movable contacts, biased to separated position, a current responsive bimetallic strip restraining such movement of said contacts, a rigid connector leading to the exterior of the circuit breaker, the interior end of said connector having .a center strip bent from its normal plane, the

remaining side pieces having their ends bent over to provide retaining flanges, a block dis- JOHN G. JACKSON. 

